This invention relates to an improved stop-motion apparatus particularly but not necessarily exclusively adapted for detecting breakage, run-out and/or excessive slackening of running sliver strands passing from a creel to the drafting rolls of a textile sliver-drafting machine.
Prior U.S. Patents of possible relevance to the present invention are Nos. 2,553,335, 2,670,503, 2,712,676, 2,734,956, 3,295,170, 3,305,896, 3,330,016, 3,404,524, 3,510,862 and 3,612,791.
There are many different types of stop-motion apparatuses employing a member which is normally maintained in a first position by engagement with a running textile strand and which, in the absence of such engagement, moves to a second position and actuates an electrical circuit. In most of the prior stop-motion apparatuses, actuation of the electrical circuit is effected by closure of electrical switch contacts which are exposed to a greater or lesser extent to the ambient air within the textile mills where such apparatuses are used. This is undesirable since such air frequently contains lint, dust, moisture and the like which detrimentally affects the operation of the exposed switch contacts. In recognition of the foregoing fact, there have also been proposed other stop-motion apparatuses employing switching means, such as glass encapsulated reed contact switches, normally open and actuable by magnetic forces, whose contacts are in an inert gas and not exposed to the ambient air. While glass encapsulated reed switches possess the foregoing advantage, they are, as compared to conventional switches, more subject to damage from accidental impacts which they might receive during use. The foregoing considerations are particularly relevant in connection with a stop-motion apparatus associated with a running array of sliver strands passing from a creel to the drafting rolls of a silver-drafting machine. From the viewpoint of their not being readily affected by lint and the like, the use of glass encapsulated reed switches in such a stop-motion apparatus is desirable. On the other hand, the provision of a separate reed switch in association with each strand of the sliver array would entail significant expense. Moreover, a stop-motion apparatus used for the above-noted purpose inevitably is subjected to some accidental impacts during use, as from engagement by the sliver cans moved to and from the creel area and/or by automatic or manual cleaning devices used for removing lint and the like from such creel area. A further problem is that of snagging of the running sliver strands on contact surfaces of switch or switch actuator members, and/or a movement of the running strands to spaces between such coacting members to provide jamming and strand parting creating an "end down" condition or a failure to maintain the running strands separated from one another when they leave the stop-motion device.